What's in this directory?

These are files containing live images for the Debian GNU/Linux
operating system. They are specifically for the i386
architecture.

There are multiple different files here, corresponding to the
different desktop environments..

How do I use these files?

The files here are bittorrent files. Use
a bittorrent
client program to download the contents of the complete ISO image
files in a peer-to-peer manner. You should end up with an exact copy
of each ISO image as though you'd downloaded it directly via HTTP or
FTP.

Once you have downloaded all the ISO images you want, you will
typically need to write them to media, either writeable DVD or a USB
stick.

How can I verify my download is correct and exactly what has
been created by Debian?

There are files here (SHA1SUMS, SHA256SUMS, etc.) which contain
checksums of the images. These checksum files are also signed - see
SHA1SUMS.sign, SHA256SUMS.sign, etc. Once you've downloaded an image,
you can check: